References of "Dufrasne, Isabelle"
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See detailEffects of environmental factors on yield and milking number in dairy cows milked by an automatic system located in pasture
Dufrasne, Isabelle ULg; Robaye, Vincent ULg; Knapp, Emilie ULg et al

Poster (2011)

Nowadays, farmers have to manage larger herds but want, at the same time, benefit from a normal social life. The milking robot can bring solutions. Its use can reduce physical labour and allow flexibility ... [more ▼]

Nowadays, farmers have to manage larger herds but want, at the same time, benefit from a normal social life. The milking robot can bring solutions. Its use can reduce physical labour and allow flexibility. This technology results in a reduction in grazing even through grazing appears as a natural practice which is appreciated by the consumers. This project aims to develop strategies to use milking robots in pasture in order to benefit from advantages regarding feeding costs as well as animal welfare and health. It aims to study the effects of grass height, animal, days in milk, rotation cycle number and distance from grazed paddocks on daily milk yield and milking number of grazed cows. [less ▲]

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See detailNitrogen excretions in dairy cows on a rotational grazing system: effects of fertilization type, days in the paddock and time period.
Dufrasne, Isabelle ULg; Robaye, Vincent ULg; Istasse, Louis ULg et al

in Schnyder, Hans; Isselstein, J.; Taube, F. (Eds.) et al Grassland in a changing world (2010, September)

The present study aims to quantify nitrogen (N) excretions in dairy cows on a rotational grazing system with different types of fertilization (mineral N, slurry and compost) after 3 or 5 days in the ... [more ▼]

The present study aims to quantify nitrogen (N) excretions in dairy cows on a rotational grazing system with different types of fertilization (mineral N, slurry and compost) after 3 or 5 days in the paddock and during two different periods in June and September. Individual samples of faeces and urine were collected to assess N excretions from cows in the paddocks. The urea content in milk from the tank or from the individual cows was also measured. N intake was higher on day 3 compared to day 5 (465 vs 425 g d-1, P<0.001) and in September as compared to June (488 vs 425 g d-1, P<0.001) but was not influenced by the fertilization type. The amount of excreted urinary N was significantly higher in the mineral N group than in the two other groups (272 vs 226 g d-1; P<0.001). The N excretion in faeces and urines decreased with days (92 vs 84 g d-1, P<0.01; 256 vs 228 g d-1, P<0.001 respectively for days 3 and 5). Urinary N excretion was lower in June than in September (181 vs 302 g d-1, P<0.001) while the N excretion in the faeces was higher (96 vs 80 g d-1, P<0.01). [less ▲]

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See detailGrazing with a mobile milking robot
Dufrasne, Isabelle ULg; Robaye, Vincent ULg; Istasse, Louis ULg et al

in Schnyder, Hans; Isselstein, J.; Taube, F. (Eds.) et al Grassland in a changing world (2010, September)

The size of dairy cow herds in Europe is increasing. Farmers have to manage larger herds but want, at the same time, benefit from a normal social life. So, the milking robot can bring solutions. Its use ... [more ▼]

The size of dairy cow herds in Europe is increasing. Farmers have to manage larger herds but want, at the same time, benefit from a normal social life. So, the milking robot can bring solutions. Its use can reduce physical labour and allow flexibility. During the past 10 years, the number of milking robots has been increased in Europe. In farm practice, this technology has resulted in a reduction in the amount of grazing even though grazing appears as a natural practice which is appreciated by the consumers. At the experimental farm of the University of Liège, we are developing the concept of a mobile milking robot in collaboration with a private company. This prototype will allow cows to graze and could be moved to different locations on pastures during the grazing season. The prototype will be used indoors during the end of the winter season and will be moved outdoor during the 2010 grazing season. The feasibility of this prototype has to be tested in the field. Milk production and quality, the number of visits and the grazing parameters will be recorded. Different equipments in view to attract the cows to the robot as the presence of a cow brush, the location of the drinking point, will be compared. The behaviour of animals will be also assessed. [less ▲]

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See detailTowards a revison of the dairy cow's standard for nitrogen production: justification and what are consequences for soil link rate of dairy farms
Lambert, Richard; De Toffoli, M.; Dufrasne, Isabelle ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14

Towards a revison of the dairy cow's standard for nitrogen production: justification and what are consequences for soil link rate of dairy farms. At present, the dairy cow's standard of nitrogen ... [more ▼]

Towards a revison of the dairy cow's standard for nitrogen production: justification and what are consequences for soil link rate of dairy farms. At present, the dairy cow's standard of nitrogen production in Walloon region is 90 kg per year. This standard is used to calculate the "soil link rate" of farms, a balance between the organic nitrogen to be spread on land and the quantity legally authorized considering grassland and arable land area. This standard is appreciably lower than that fixed by other member states and was criticized by the European Commission during the negotiations having ended in the second program of sustainable nitrogen management. Further to new studies, it seems that the gaseous loss of nitrogen averages in buildings and during the storage is weaker than the 15% value which was used to justify this 90 kg standard. It also seems that there are big differences of average dairy production and average rate of urea according to the agricultural regions and consequently that regional production standards correspond better to the reality. On basis of these mean values, the dairy cow's annual productions of nitrogen vary between 81 kg per year in grassy region of Fagne and 99 kg per year in Haute Ardenne and in grassy region from Liege. For the Walloon region in general, the average production is 94 kg per year. The adoption of different values of dairy cow's nitrogen production by region would lead to an increase of 8% of the soil link rate of dairy farms in Haute Ardenne and of 7% in grassy region from Liege and a decrease of 7% in grassy region of Fagne. [less ▲]

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See detailInfluence of the fertilization type, the day in the paddock and the month on nitrogen rejections in dairy cows
Dufrasne, Isabelle ULg; Istasse, Louis ULg; Robaye, Vincent ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14

Influence of the fertilization type, the day in the paddock and the month on nitrogen rejections in dairy cows. The present study aims to quantify nitrogen (N) rejections in dairy cows on a rotational ... [more ▼]

Influence of the fertilization type, the day in the paddock and the month on nitrogen rejections in dairy cows. The present study aims to quantify nitrogen (N) rejections in dairy cows on a rotational grazing system with different types of fertilization (compost, slurry and mineral N) at two different days in the paddock (days 3 and 5) and during two different periods (June and September). Grass yield and height were measured along with the chemical composition. The live weight was recorded when the cows moved into the paddock and milk yields was recorded at each milking. N intakes were measured on the basis of the energy requirement. When the cows were in the paddocks, individual samples of faeces and urine were collected to assess N rejections. The urea content in milk from the tank or from the individual cows was also measured. N intake was higher on day 3 than on day 5 and in September as compared with in June but was not influenced by the fertilization. The amount of N produced in milk was not influenced either by the fertilization, by the day on the paddock or by the month. The amount of urinary N was significantly higher in the N mineral group than in the two other groups. The N excretion in faeces and urines was higher on day 3 than on day 5. In June, the N excretion by the urine was lower than in September while the N excretion by the faeces was higher. Equations were calculated in order to estimate the N excretion by the urine in grazing dairy cows from the urea content in milk of a group of cows. [less ▲]

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See detailStudy on environmental factors influencing the urea content of cow milk in Wallonia (Belgium)
Dufrasne, Isabelle ULg; Istasse, Louis ULg; LAMBERT, René ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14

Study on environmental factors influencing the urea content of cow milk in Wallonia (Belgium). The urea content in tank milk is currently assessed in Wallonia (Belgium) for all milk producers by the ... [more ▼]

Study on environmental factors influencing the urea content of cow milk in Wallonia (Belgium). The urea content in tank milk is currently assessed in Wallonia (Belgium) for all milk producers by the Comite du lait. A statistical analysis was carried out on 5,675,758 data collected over the 2002-2008 period in order to study the variation in the urea content in milk from cows according to the months of the years and the agronomy areas. The data were analyzed with a linear model (proc GLM) including the fixed effects of the area, the month of sampling, the year and the interactions. The fat and proteins contents in milk were used as covariables. The average urea content in milk over the six years was 258 mg.l(-1). A proportion of 19% of the contents were over 350 mg.l(-1)and 10% over 400 mg.l(-1). The model explained 35% of the variation of the urea content. Within the model, the agronomy area was the most explicative component (44%). It was followed by the area-month interaction (18.6%), the protein content (17.8%) and the month (10.5%). The variation of the urea content in milk could be mainly explained by the differences in the diets offered to the lactating dairy cows according to the agronomy areas. The composition of the diets varies with the crops produced and therefore with the agronomy area. Higher urea contents were observed in areas with a lot of pastures (grazing areas) than in the arable areas. In the grazing areas, feedstuffs higher in protein than in energy are consumed by the cows: the excess of protein is probably the reason for the higher urea content. The feedstuffs produced in the arable areas are more various with more diversified and balanced diets. The season influenced also the urea content, a higher urea content being observed during the summer period as compared with the winter period. The changes could be explained by dietary differences between the indoor winter period and the grazing period in Summer. During the indoor period, the dairy cows are offered normally a complete diet which is more balanced than during the grazing period. [less ▲]

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See detailVers une révision de la norme de production d'azote de la vache laitière : justification et conséquences sur le taux de liaison
Lambert, Richard; De Toffoli, M.; Dufrasne, Isabelle ULg et al

in Marcoen, Jean Marie; Vandenberghe, Christophe (Eds.) Acte de l'atelier "Nitrate - Eau" (2010)

Towards a revison of the dairy cow’s standard for nitrogen production: justification and what are consequences for soil link rate of dairy farms. At present, the dairy cow’s standard of nitrogen ... [more ▼]

Towards a revison of the dairy cow’s standard for nitrogen production: justification and what are consequences for soil link rate of dairy farms. At present, the dairy cow’s standard of nitrogen production in Walloon region is 90 kg per year. This standard is used to calculate the “soil link rate” of farms, a balance between the organic nitrogen to be spread on land and the quantity legally authorized considering grassland and arable land area. This standard is appreciably lower than that fixed by other member states and was criticized by the European Commission during the negotiations having ended in the second program of sustainable nitrogen management. Further to new studies, it seems that the gaseous loss of nitrogen averages in buildings and during the storage is weaker than the 15% value which was used to justify this 90 kg standard. It also seems that there are big differences of average dairy production and average rate of urea according to the agricultural regions and consequently that regional production standards correspond better to the reality. On basis of these mean values, the dairy cow’s annual productions of nitrogen vary between 81 kg per year in grassy region of Fagne and 99 kg per year in Haute Ardenne and in grassy region from Liege. For the Walloon region in general, the average production is 94 kg per year. The adoption of different values of dairy cow’s nitrogen production by region would lead to an increase of 8% of the soil link rate of dairy farms in Haute Ardenne and of 7% in grassy region from Liege and a decrease of 7% in grassy region of Fagne. [less ▲]

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See detailEtude de facteurs environnementaux influençant la teneur en urée dans le lait de vaches en Wallonie (Belgique)
Dufrasne, Isabelle ULg; Istasse, Louis ULg; Lambert, Richard et al

in Marcoen, Jean Marie; Vandenberghe, Christophe (Eds.) Actes de l'Atelier "Nitrate - Eau" (2010)

Study on environmental factors influencing the urea content of cow milk in Wallonia (Belgium). The urea content in tank milk is currently assessed in Wallonia (Belgium) for all milk producers by the ... [more ▼]

Study on environmental factors influencing the urea content of cow milk in Wallonia (Belgium). The urea content in tank milk is currently assessed in Wallonia (Belgium) for all milk producers by the Comité du lait. A statistical analysis was carried out on 5,675,758 data collected over the 2002-2008 period in order to study the variation in the urea content in milk from cows according to the months of the years and the agronomy areas. The data were analyzed with a linear model (proc GLM) including the fixed effects of the area, the month of sampling, the year and the interactions. The fat and proteins contents in milk were used as covariables. The average urea content in milk over the six years was 258 mg.l-1. A proportion of 19% of the contents were over 350 mg.l-1and 10% over 400 mg.l-1. The model explained 35% of the variation of the urea content. Within the model, the agronomy area was the most explicative component (44%). It was followed by the area-month interaction (18.6%), the protein content (17.8%) and the month (10.5%). The variation of the urea content in milk could be mainly explained by the differences in the diets offered to the lactating dairy cows according to the agronomy areas. The composition of the diets varies with the crops produced and therefore with the agronomy area. Higher urea contents were observed in areas with a lot of pastures (grazing areas) than in the arable areas. In the grazing areas, feedstuffs higher in protein than in energy are consumed by the cows: the excess of protein is probably the reason for the higher urea content. The feedstuffs produced in the arable areas are more various with more diversified and balanced diets. The season influenced also the urea content, a higher urea content being observed during the summer period as compared with the winter period. The changes could be explained by dietary differences between the indoor winter period and the grazing period in Summer. During the indoor period, the dairy cows are offered normally a complete diet which is more balanced than during the grazing period. [less ▲]

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See detailInfluence du type de fertilisation, du jour de pâturage et du mois de l’année sur les rejets azotés des vaches laitières
Dufrasne, Isabelle ULg; Istasse, Louis ULg; Robaye, Vincent ULg et al

in Marcoen, Jean Marie; Vandenberghe, Christophe (Eds.) Acte de l'atelier "Nitrate - Eau" (2010)

Influence of the fertilization type, the day in the paddock and the month on nitrogen rejections in dairy cows. The present study aims to quantify nitrogen (N) rejections in dairy cows on a rotational ... [more ▼]

Influence of the fertilization type, the day in the paddock and the month on nitrogen rejections in dairy cows. The present study aims to quantify nitrogen (N) rejections in dairy cows on a rotational grazing system with different types of fertilization (compost, slurry and mineral N) at two different days in the paddock (days 3 and 5) and during two different periods (June and September). Grass yield and height were measured along with the chemical composition. The live weight was recorded when the cows moved into the paddock and milk yields was recorded at each milking. N intakes were measured on the basis of the energy requirement. When the cows were in the paddocks, individual samples of faeces and urine were collected to assess N rejections. The urea content in milk from the tank or from the individual cows was also measured. N intake was higher on day 3 than on day 5 and in September as compared with in June but was not influenced by the fertilization. The amount of N produced in milk was not influenced either by the fertilization, by the day on the paddock or by the month. The amount of urinary N was significantly higher in the N mineral group than in the two other groups. The N excretion in faeces and urines was higher on day 3 than on day 5. In June, the N excretion by the urine was lower than in September while the N excretion by the faeces was higher. Equations were calculated in order to estimate the N excretion by the urine in grazing dairy cows from the urea content in milk of a group of cows. [less ▲]

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See detailEvaluation et proposition de révision du deuxième Programme de Gestion Durable de l'Azote en agriculture en Région wallonne (Belgique)
Vandenberghe, Christophe ULg; Benoit, Jérémie ULg; Deneufbourg, Mathieu ULg et al

in Marcoen, Jean Marie; Vandenberghe, Christophe (Eds.) Actes de l'Atelier "Nitrate - Eau" 2 au 5 juin 2009. Peyresq, France (2010)

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See detailUtilisation de la prairie permanente dans le contexte d’extensification: application en productions de viande et de lait
Cameroni, F. J. D.; Hornick, Jean-Luc ULg; Istasse, Louis ULg et al

in Annales de Médecine Vétérinaire (2008), 152(3), 138-151

Les productions animales sont soumises à des restrictions qui ont pour objectif de respecter le bien être animal et la sécurité de la chaîne alimentaire ou de contrôler les volumes de production et leurs ... [more ▼]

Les productions animales sont soumises à des restrictions qui ont pour objectif de respecter le bien être animal et la sécurité de la chaîne alimentaire ou de contrôler les volumes de production et leurs impacts environnementaux. Ces dernières restrictions imposent des mesures de réduction du chargement en animaux par hectare et du niveau de fertilisation azotée et sont réglementées dans le cadre de la Directive Nitrate (91/676/EC). L’extensification des systèmes de production répond aux mesures encouragées par les politiques agricoles qui visent à réduire l’excèdent d’azote (N) dans des systèmes de production présentant intrinsèquement de faibles efficiences d’utilisation de l’azote. Le présent travail récapitule les résultats zootechniques, phytotechniques et environnementaux des systèmes de pâturage, pendant six années, pour trois catégories d’animaux (vaches allaitantes et veaux, taureaux et vaches laitières). Des protocoles semblables ont été utilisés pour les trois catégories, à savoir, un système avec fertilisation azotée et chargement conventionnel intensif (3/3 N), un traitement avec le même chargement et une fertilisation azotée réduite d’un tiers (2/3 N) et un traitement sans application de fertilisation azotée (0 N) avec un chargement adapté. Les résultats montrent qu’une réduction d’un tiers de la fertilisation azotée peut être envisagée pour réduire les excédents d’azote des systèmes de pâturage alors que les systèmes extensifs présentent des efficiences plus hautes d’utilisation de l’azote et des bilans azotés plus favorables, sans affecter le niveau ni la qualité des produits. [less ▲]

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See detailSoil-applied selenium effects on tissue selenium concentrations in cultivated and adventitious grassland and pasture plant species
Hambuckers, Alain ULg; Dotreppe, Olivier ULg; Hornick, Jean-Luc ULg et al

in Communications in Soil Science & Plant Analysis (2008), 39(5-6), 800-811

According to international nutritional standards, plant selenium (Se) concentrations in Belgium are too low. To correct this situation, adding Se in fertilizers for pastures and grasslands is suggested ... [more ▼]

According to international nutritional standards, plant selenium (Se) concentrations in Belgium are too low. To correct this situation, adding Se in fertilizers for pastures and grasslands is suggested, similar to activities in Finland. However, there is a lack of data on meadow plant species' ability to absorb Se. Therefore, a pot experiment was initiated using 24 meadow plant species cultivated on a Belgian cambisol receiving standard fertilizer treatment, with or without the addition of 9 g Se ha(-1) yr(-1) as sodium selenate. Soil Se analysis confirmed the low Se status of the native soil. Mean foliar Se concentration in the control group was 0.05 mg kg(-1). Because plant deficiency may occur at levels less than 0.10 mg Se kg(-1), data provided further evidence for Se deficiency in Belgium plant production. When grown with Se, plant species showed wide variations for Se concentration, ranging from 0.08 to 0.49 mg Se kg(-1). All values were less than 2 mg Se kg(-1), the suggested threshold toxicity level for dairy cattle. There were two different types of plants in terms of response to Se fertilization. Most of the tested plants were known as nonaccumulators. There were also two probable secondary accumulators: Sinapis arvensis and Melilotus albus. Finally, one has to question the reliability of plant Se enhancement using this method when floristic composition is poorly controlled. [less ▲]

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